在正常情况下,保护零线不流过电流,所以人体可以触及。
参考答案:错
—Tom, shall we set up a student volunteer project in our school?
—______.[ ]
A. I don't want to join you
B. Thank you for your help
C. That's a good idea
用“王水”(浓盐酸与浓硝酸的混合物)溶解黄金后得到四氯合金酸(HAuCl4),
其中金元素(Au)的化合价为
A.+3
B.+2
C.+1
D.+4